My 1992 944 "backfires" when I let off the gas and it starts to decelerate. It's not incredibly loud and does not always do it but does it quite a bit.

It's just some pop, pop...pop sounds coming from the rear of the car.

Any ideas?

 

thats generally an indication of air leaks in the exhaust manifold combined with running too rich.

why your car is doing it? no idea.